This invention relates to tornado warning systems. More specifically, it relates to a tornado warning system which senses electromagnetic signals produced by tornados.
Tornados are a serious problem in many areas of the world. They often cause extensive property damage, serious injury, and even loss of life. Various devices and systems have been used in an attempt to detect tornados. If a detector warns a person about the approach of a tornado, the person may go to a basement or take other action to minimize the risk of injury or death.
Various tornado warning systems have been developed. Although the warning systems have provided varying degrees of usefulness, they are often subject to one or more of many disadvantages. One common disadvantage is the inability of some warning systems to distinguish between a tornado and a less severe storm. Depending upon the type of warning system, one must accept a relatively large of number of false positives (incorrect tornado warnings) in order to insure that the system will detect real tornados in a timely fashion. For example, a tornado warning system which uses a threshold arrangement requires that the threshold be set very carefully. If the threshold is set too low, a very brief severe moment in an otherwise moderate storm may falsely trigger the tornado alarm. On the other hand, if the threshold is set too high, the warning system may not detect a tornado or may detect it too late for evasive action. Some tornado warning systems are relatively unreliable, complex, expensive, and/or difficult to maintain in proper operation.
An example of a particular tornado warning device is that described in U.S. Pat. No. 3,810,137, issued to Bacon et al. on May 7, 1974. The Bacon patent discloses a tornado alarm which detects electromagnetic radiation generated by a tornado. A threshold detector is used to trigger an audible alarm and a warning light.